Temperature Field Analysis Of Components In Medium Voltage Switch Cabinet And Development Of Its Monitoring System

With the rapid development of the national economy and the increase of electricpower consumption, the distribution network becomes more complex and its load isincreasing. Hence, for insuring the robust and stability of the grid, devices of thedistribution network should be monitored and automation level should be improved.10kV medium voltage switch cabinet is a key device in distribution network and itsdevelopment aims at high reliability, low maintenance, miniaturization, integration andhigh intelligence. While, high integration leads to too many components andcomplicated electric and mechanical structures. Therefore, the fault would be happenedfrequently. Hence, applying online monitoring devices to find fault in time has greatmeaning to the whole grid. Overheat fault ever happened in one NXAIR switch cabinetin some switching station in Chongqing. For this situation, temperature fielddistribution of cable end connector and vacuum breaker of switch cabinet weresimulated. Based on the results, an online monitoring system was developed withcombination of infrared sensors, single-chip, GSM communication module, PCBdesign and program compiling with Labview software. The detailed work is as follows:Based on heat transfer theory, multi-physics coupling simulation software wasadopted to calculate the temperature field distribution of cable end connecter andvacuum breaker. At first, two models were set up respectively. Then, materials andphysics environment were set. After meshing, the results were obtained and weakerpoints were found by comparing distribution feature.②Based on C8051F021single-chip, hardware was developed which combinesinfrared sensor, master control unit, display unit and communication unit. The sensorscapture data without contact. With drive program, master control unit manages eachunit such as A/D converter, data display, sending message to appointed phone andtransferring data to upper computer system. In addition, upper computer software isdeveloped in Labview which has the functions of data display, data analysis and datastorage.③The entire system was set in the site and taken trial operation. Combinationforecast algorithm was compiled to forecast the data alter trend. It has great meaningfor timely detection and warning of potential fault.